Fig. 6.
Discrimination against Glu-tRNAGln by archaeal EF-1α. TLC images showing spots corresponding to acylated (Gln-Ap*) and deacylated (Ap*) tRNAs (left panels) were quantified to give the fraction of (a) Gln-tRNAGln, (b) Glu-tRNAGln and (c) Glu-tRNAGlu in the presence of 2.2 μM activated EF-1α (inverted triangles) or in the presence of activated EF-1α following proteinase K incubation for 10 minutes (triangles). When EF-1α is removed by proteolysis, the rate constants for spontaneous deacylation are 0.036 min−1, 0.025 min−1, and 0.025 min−1 for the three aminoacyl-tRNAs, respectively (blue traces). In the presence of activated EF-1α, the rate constants are: 0.0015 min−1 for Gln-tRNAGln, 0.013 min−1 for Glu-tRNAGln, and 0.003 min−1 for Glu-tRNAGlu, respectively (black traces).